1. Field of the Invention
The present invention relates to a printing apparatus using a continuous sheet.
2. Description of the Related Art
Japanese Patent Laid-Open No. 2008-126530 discloses a printing apparatus that performs duplex printing on both of the front and rear surfaces of a long continuous rolled sheet in an inkjet manner.
Japanese Patent Laid-Open No. 8-335021 discloses a mechanism for pulling a processing unit to perform a jam recovery process when a jam occurs during sheet conveyance in a printing apparatus that prints on a cut sheet. If a jam of a sheet extending over two processing units occurs, the two units are pulled out of an apparatus while the units are being coupled to each other. Thus, the jam recovery process can be performed without tearing the sheet between the units.
In the apparatus disclosed in Japanese Patent Laid-Open No. 2008-126530, consideration is not given to the recovery process performed when it is difficult to convey a sheet because of the occurrence of a jam during sheet conveyance (hereinafter, referred to as “sheet conveyance jam”). Accordingly, if a jam occurs, an operator has to remove the entire sheet in the apparatus and resume printing from the beginning of a print job. In other words, if a jam occurs, the amount of wasted sheet and the amount of wasted ink are large. In addition, it takes much time and effort to perform a jam recovery operation.
In the apparatus disclosed in Japanese Patent Laid-Open No. 8-335021, since a sheet to be used is a cut sheet having a short length in a sheet conveying direction, a single sheet extends over two units at most. In a printing apparatus using a continuous sheet, however, a single continuous sheet extends over many processing units at one time. When a jam occurs, it is not realistic to pull all of the units out of the apparatus while the units are being coupled to one another. If an operator tries to pull one of the units after the occurrence of a jam, the operator cannot smoothly pull the unit because the sheet remaining in a sheet conveying path is caught. If the unit is forced to be pulled, the sheet is forced to be drawn, so that the unit and at least one adjacent unit may be damaged. Alternatively, the sheet may be torn and a piece of the torn sheet may be left in a place from which the piece cannot be removed.